6645191 has 16 divisors (see below), whose sum is σ = 7938048. Its totient is φ = 5443200.

The previous prime is 6645187. The next prime is 6645209. The reversal of 6645191 is 1915466.

It is not a de Polignac number, because 6645191 - 2² = 6645187 is a prime.

It is an Ulam number.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (6645131) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 24386 + ... + 24656.

It is an arithmetic number, because the mean of its divisors is an integer number (496128).

Almost surely, 2^6645191 is an apocalyptic number.

6645191 is a deficient number, since it is larger than the sum of its proper divisors (1292857).

6645191 is a wasteful number, since it uses less digits than its factorization.

6645191 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 422.

The product of its digits is 6480, while the sum is 32.

The square root of 6645191 is about 2577.8267979056. The cubic root of 6645191 is about 188.0048946213.

The spelling of 6645191 in words is "six million, six hundred forty-five thousand, one hundred ninety-one".